Question

How is it that ice-cream appears cooler to the mouth than water at $0^{\circ }C$?

Answer 1

Ice-cream has less heat energy as compared to that of water at $0^{o}C$. It's because the fact that water has latent heat of fusion present in it. But ice-cream is in solid form; i.e. it has released its latent heat of fusion of while coming in solid state. So due to less energy of ice-cream in comparison to that of water; ice-cream appears cooler to mouth than that of water at $0^{o}C$.